NetBSD/usr.sbin/wpa/l2_packet.c

296 lines
6.9 KiB
C

/* $NetBSD: l2_packet.c,v 1.5 2007/05/27 03:14:32 christos Exp $ */
/*
* WPA Supplicant - Layer2 packet handling
* Copyright (c) 2003-2004, Jouni Malinen <jkmaline@cc.hut.fi>
* Copyright (c) 2005, Sam Leffler <sam@errno.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* Alternatively, this software may be distributed under the terms of BSD
* license.
*
* See README and COPYING for more details.
*/
/*
* NetBSD-specific implementation.
*
* Based on:
* $FreeBSD: src/usr.sbin/wpa/l2_packet.c,v 1.3 2006/03/07 05:54:19 sam Exp $
*/
#include <sys/types.h>
#include <sys/param.h>
#include <sys/ioctl.h>
#include <sys/socket.h>
#include <sys/sysctl.h>
#include <net/if.h>
#include <net/if_dl.h>
#include <net/route.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <stdlib.h>
#include <string.h>
#include <stdio.h>
#include <errno.h>
#include <pcap.h>
#include "common.h"
#include "eloop.h"
#include "l2_packet.h"
struct l2_packet_data {
pcap_t *pcap;
char ifname[100];
u8 own_addr[ETH_ALEN];
void (*rx_callback)(void *ctx, const u8 *src_addr,
const u8 *buf, size_t len);
void *rx_callback_ctx;
int rx_l2_hdr; /* whether to include layer 2 (Ethernet) header in calls
* to rx_callback */
};
int
l2_packet_get_own_addr(struct l2_packet_data *l2, u8 *addr)
{
memcpy(addr, l2->own_addr, ETH_ALEN);
return 0;
}
void
l2_packet_set_rx_l2_hdr(struct l2_packet_data *l2, int rx_l2_hdr)
{
l2->rx_l2_hdr = rx_l2_hdr;
}
int
l2_packet_send(struct l2_packet_data *l2,
const u8 *dst_addr, u16 proto, const u8 *buf, size_t len)
{
if (!l2->rx_l2_hdr) {
int ret;
struct l2_ethhdr *eth = malloc(sizeof(*eth) + len);
if (eth == NULL)
return -1;
memcpy(eth->h_dest, dst_addr, ETH_ALEN);
memcpy(eth->h_source, l2->own_addr, ETH_ALEN);
eth->h_proto = htons(proto);
memcpy(eth + 1, buf, len);
ret = pcap_inject(l2->pcap, (u8 *) eth, len + sizeof(*eth));
free(eth);
return ret;
} else
return pcap_inject(l2->pcap, buf, len);
}
int
l2_packet_get_ip_addr(struct l2_packet_data *l2, char *buf, size_t len)
{
pcap_if_t *devs, *dev;
struct pcap_addr *addr;
struct sockaddr_in *saddr;
int found = 0;
char err[PCAP_ERRBUF_SIZE + 1];
if (pcap_findalldevs(&devs, err) < 0) {
wpa_printf(MSG_DEBUG, "pcap_findalldevs: %s\n", err);
return -1;
}
for (dev = devs; dev && !found; dev = dev->next) {
if (strcmp(dev->name, l2->ifname) != 0)
continue;
addr = dev->addresses;
while (addr) {
saddr = (struct sockaddr_in *) addr->addr;
if (saddr && saddr->sin_family == AF_INET) {
snprintf(buf, len, "%s",
inet_ntoa(saddr->sin_addr));
found = 1;
break;
}
addr = addr->next;
}
}
pcap_freealldevs(devs);
return found ? 0 : -1;
}
void
l2_packet_notify_auth_start(struct l2_packet_data *l2)
{
}
static void
l2_packet_receive(int sock, void *eloop_ctx, void *sock_ctx)
{
struct l2_packet_data *l2 = eloop_ctx;
pcap_t *pcap = sock_ctx;
struct pcap_pkthdr hdr;
const u_char *packet;
struct l2_ethhdr *ethhdr;
unsigned char *buf;
size_t len;
packet = pcap_next(pcap, &hdr);
if (packet == NULL || hdr.caplen < sizeof(*ethhdr))
return;
ethhdr = (struct l2_ethhdr *) packet;
if (l2->rx_l2_hdr) {
buf = (unsigned char *) ethhdr;
len = hdr.caplen;
} else {
buf = (unsigned char *) (ethhdr + 1);
len = hdr.caplen - sizeof(*ethhdr);
}
l2->rx_callback(l2->rx_callback_ctx, ethhdr->h_source, buf, len);
}
static int
l2_packet_init_libpcap(struct l2_packet_data *l2, unsigned short protocol)
{
bpf_u_int32 pcap_maskp, pcap_netp;
char pcap_filter[100], pcap_err[PCAP_ERRBUF_SIZE];
struct bpf_program pcap_fp;
pcap_lookupnet(l2->ifname, &pcap_netp, &pcap_maskp, pcap_err);
l2->pcap = pcap_open_live(l2->ifname, 2500, 0, 10, pcap_err);
if (l2->pcap == NULL) {
fprintf(stderr, "pcap_open_live: %s\n", pcap_err);
fprintf(stderr, "ifname='%s'\n", l2->ifname);
return -1;
}
if (pcap_datalink(l2->pcap) != DLT_EN10MB &&
pcap_set_datalink(l2->pcap, DLT_EN10MB) < 0) {
fprintf(stderr, "pcap_set_datalinke(DLT_EN10MB): %s\n",
pcap_geterr(l2->pcap));
return -1;
}
snprintf(pcap_filter, sizeof(pcap_filter),
"ether dst " MACSTR " and ether proto 0x%x",
MAC2STR(l2->own_addr), protocol);
if (pcap_compile(l2->pcap, &pcap_fp, pcap_filter, 1, pcap_netp) < 0) {
fprintf(stderr, "pcap_compile: %s\n", pcap_geterr(l2->pcap));
return -1;
}
if (pcap_setfilter(l2->pcap, &pcap_fp) < 0) {
fprintf(stderr, "pcap_setfilter: %s\n", pcap_geterr(l2->pcap));
return -1;
}
pcap_freecode(&pcap_fp);
/*
* When libpcap uses BPF we must enable "immediate mode" to
* receive frames right away; otherwise the system may
* buffer them for us.
*/
{ unsigned int on = 1;
if (ioctl(pcap_fileno(l2->pcap), BIOCIMMEDIATE, &on) < 0) {
fprintf(stderr, "%s: cannot enable immediate mode on "
"interface %s: %s\n",
__func__, l2->ifname, strerror(errno));
/* XXX should we fail? */
}
}
eloop_register_read_sock(pcap_get_selectable_fd(l2->pcap),
l2_packet_receive, l2, l2->pcap);
return 0;
}
static int
eth_get(const char *device, u8 ea[ETH_ALEN])
{
struct if_msghdr *ifm;
struct sockaddr_dl *sdl;
u_char *p, *buf;
size_t len;
int mib[] = { CTL_NET, AF_ROUTE, 0, AF_LINK, NET_RT_IFLIST, 0 };
if (sysctl(mib, 6, NULL, &len, NULL, 0) < 0)
return -1;
if ((buf = malloc(len)) == NULL)
return -1;
if (sysctl(mib, 6, buf, &len, NULL, 0) < 0) {
free(buf);
return -1;
}
for (p = buf; p < buf + len; p += ifm->ifm_msglen) {
ifm = (struct if_msghdr *)p;
sdl = (struct sockaddr_dl *)(ifm + 1);
if (ifm->ifm_type != RTM_IFINFO ||
(ifm->ifm_addrs & RTA_IFP) == 0)
continue;
if (sdl->sdl_family != AF_LINK || sdl->sdl_nlen == 0 ||
memcmp(sdl->sdl_data, device, sdl->sdl_nlen) != 0)
continue;
memcpy(ea, LLADDR(sdl), sdl->sdl_alen);
break;
}
if (p >= buf + len) {
errno = ESRCH;
free(buf);
return -1;
}
free(buf);
return 0;
}
struct l2_packet_data *
l2_packet_init(const char *ifname, const u8 *own_addr, unsigned short protocol,
void (*rx_callback)(void *ctx, const u8 *src_addr,
const u8 *buf, size_t len),
void *rx_callback_ctx, int rx_l2_hdr)
{
struct l2_packet_data *l2;
l2 = malloc(sizeof(struct l2_packet_data));
if (l2 == NULL)
return NULL;
memset(l2, 0, sizeof(*l2));
strncpy(l2->ifname, ifname, sizeof(l2->ifname));
l2->rx_callback = rx_callback;
l2->rx_callback_ctx = rx_callback_ctx;
l2->rx_l2_hdr = rx_l2_hdr;
if (eth_get(l2->ifname, l2->own_addr) < 0) {
fprintf(stderr, "Failed to get link-level address for "
"interface '%s'.\n", l2->ifname);
free(l2);
return NULL;
}
if (l2_packet_init_libpcap(l2, protocol) != 0) {
free(l2);
return NULL;
}
return l2;
}
void
l2_packet_deinit(struct l2_packet_data *l2)
{
if (l2 == NULL)
return;
if (l2->pcap) {
eloop_unregister_read_sock(pcap_get_selectable_fd(l2->pcap));
pcap_close(l2->pcap);
}
free(l2);
}